Really? I certainly hope not!
I plan my fuel usage carefully, and rarely miss by more a gallon, and, thanks to ATC routing shortcuts, almost always land with at least a gallon or two more than I had planned to use if I flew the full expected route. I’ve tweaked the ForeFlight performance profile for our plane many times and it’s so dialed in now that it’s rarely more than 5 minutes or 1 gallon off of actual.
In right in the middle of adding CiES senders on my G1.
My factory gauges were fairly accurate except the tanks looked much emptier than they were when selected at lower fuel volumes.
I learned that Cirrus put one level sender in the header tank (think buffer tank between the main tank and the fuel selector valve) and the second at the outboard end of the wing tank. This created two problems. A dead spot around 26-30 gallons where neither sender would register a change in fuel level, and the header tank lagging the main tank when the fuel level was lower.
The latest CiES install moves the second sensor from the header tank to the inboard end of the main tank. The sad part of this is there is already a place to mount the fuel sender on that end of the tank, but for some reason Cirrus decided to not use that mounting location and instead put in the header tank. This makes it relatively easy to move the new sensor to the proper location that eliminates both issues with the header tank sensor. And the new location is easier to get to for service issues.
Here is a pic of the new sender location with the holes added.
As for the varying readings in flight verses on the ground. The Cirrus AMM says to calibrate the fuel senders with the plane level - 0 degrees on the door sill. But when on the gear most planes sit about 2 degrees nose high. In cruise, the only time I see 0 degrees is when cruising at full power. At normal LOP cruise or when flying in the teens the plane is 2-2.5 degrees nose high.
A possible solution is to calibrate the gauges on the gear, not with a level plane. That way you get more accurate readings on the ground and in LOP cruise. There is no perfect answer here given the very flat geometry of our fuel tanks.
Pitch up or down makes negligible difference in accurate indication.
Proper installation and calibration procedures make the difference.
I don’t recommend “rolling your own” when calibrating the system.
Ballpark estimate of cost 2026 to install these? Thanks
That sender location in the main tank on the G2 was intentional — Cirrus saw early on that the header tank placement wasn’t ideal and designed in a future home for it. The G3 is where they actually made the move.
The reason it became urgent, is a good piece of aviation history. After TWA 800, the FAA reversed course on fuel tank explosion assumptions. The prior logic — that 100LL tanks are too rich to combust — was essentially set aside, and any manufacturer updating fuel quantity was now required to use an intrinsically safe design. That forced every major OEM’s hand simultaneously:
CiES exists because of that regulatory moment. Our goal was to go further — eliminate all electrical contact with fuel entirely and measure it directly, making the system immune to fuel chemistry whether it’s 100LL, unleaded, or whatever comes next. We’ve been standard on Cirrus since 2012 and with Cessna since 2024.
So that prepared location in the G2 main tank? Cirrus was already thinking ahead.
The last G2 went 30 Hrs. G3 are easier but with Fiki I would image a similar number. Corporate Air in Bellingham had it dialed. We are working on video’s and clarified instructions to make the change as easy as possible.
Cirrus has the exclusive rights to sell the CiES upgrade kits.
The G3 kit is $5300, the G1 $5400 (retail prices).
Installation takes from 24 to 30 hours.
You will want to go to a trained installer. Experience dramatically reduces the installation time.
I would disagree with number three. At least in my airplane. I have found the totalizer to be incredibly accurate. This is historically true with mechanical fuel gauges, but I have found my fuel gauges to be within 1 gallon or so accuracy every time it’s filled
Upgraded to CiES sensors in my G3 about 4 years ago. Work done by John Fisher at Blackhawk in Glendale, AZ. $8K for parts and labor.
I monitored fill levels and totalizer vs CiES readings obsessively for a year and never found them to be more than a couple gallons off. I think the key is in calibration. If you are having wide swings in fuel readings, your system has probably not been calibrated correctly.
Expensive yes, but feeling confident about your remaining fuel is priceless.
Best upgrade I’ve done.
And lets be honest, the original Cirrus analog guages were/are crap.
My CiES systen, installed in my G2 this year is never off more than 1 gallon, typically half a gallon.
